1. Field of the Invention
The present invention relates to an LED (Light Emitting Diode) device used as an auxiliary light source of a CCD (charge coupled device) or a CMOS (Complementary Metal Oxide Semiconductor) camera or as a backlight source of an LCD (Liquid Crystal Display). More specifically, the present invention relates to an LED device having superior color reproduction characteristic and emitting bright white light, including a combination of a light emitting element and a fluorescent substance excited by the light emitting element.
2. Description of the Background Art
As a conventional white light emitting device using an LED, a white LED device has been known (see, for example, Japanese Patent Laying-Open No. 2002-064220), which includes a combination of a blue light emitting element having peak emission wavelength of about 460 nm and a YAG based fluorescent substance emitting yellow fluorescent light excited by the blue light emitting element, emitting white light as a mixed emission of blue and yellow light.
The white LED device described above, however, attains quasi-white emission by the combination of blue light and fluorescent light of yellow as a complementary color of blue, and therefore, color reproduction characteristic of red, in particular, has been unsatisfactory.
As another example, a white LED device including a combination of LEDs having peak emission wavelengths of red, green and blue as three primary colors of light, for emitting white light as a mixed emission has also been known.
In such a white LED device, however, peak emission width of each light emitting element is narrow, and therefore, it has been difficult to attain bright white light with satisfactory color reproduction characteristic.